Washington increased the pressure after waiting a week for Iran's response to the package, which proposes shipping out low-enriched uranium (LEU) from Iran to be converted into fuel for a Tehran reactor.
"The president's time is not unlimited, this was not about talking for the sake of talking," said White House spokesman Robert Gibbs.
"This was about reaching an agreement that just a few weeks ago seemed to be something that the Iranians wanted," Gibbs said.
The International Atomic Energy Agency (IAEA), said on Thursday it has received an "initial response" from Iran to the deal, but the Iranian news service IRNA said that was not Tehran's "answer" to the UN-backed plan.
IRNA also reported, quoting an unnamed informed source, that the Islamic Republic was "ready" to have more negotiations in the reactor project.
The deal would have the affect of taking substantial uranium supplies out of Iran and leaving the Islamic Republic without sufficient material to make a nuclear weapon, at least from stockpiles known to the international community.
Iran denies western claims that it is bent on producing nuclear weapons, but the crisis escalated in September, when it and the United States revealed the existence of a previously unexposed nuclear plant at Qom.
From the US point of view, the deal would give Washington and its allies time to negotiate a more far-reaching agreement with Iran, and defuse the crisis.
Amid growing international impatience, IRNA indicated Tehran's initial message to the IAEA was "not an answer to the draft agreement."
Iran would state its full position after more negotiations, the agency said.
But IRNA reported that Iran was expected to insist it will hand over its LEU at the same time it receives the fuel for the Tehran reactor. The agency did not elaborate.
Iran had been initially due to give its response to the deal by October 23.
US Secretary of State Hillary Clinton said on Friday the United States was still trying to determine the extent of Iran's initial response to the IAEA.
"We are working to determine exactly what they are willing to do, whether this was an initial response that is an end response or whether it's the beginning of getting to where we expect them to end up," she told CNN.
The plan calls for Iran to export to Russia more than 2,640 pounds (1,200 kilos) of its 3.5 percent low-enriched uranium (LEU) for refining up to 20 percent to fuel a Tehran reactor that makes medical isotopes.
France would then fashion the material into fuel rods for the reactor.
